1. Field of the Invention
The present invention relates to a shift control system for an automatic transmission and, more particularly, to a technique of manual selection of a demand for a shift feel.
2. Description of the Prior Art
An automatic transmission has as its function to select a shifting stage by selectively hydraulically operating a plurality of friction elements such as a clutch and a brake, and to change the selected shifting stage to the other by shifting a friction element to be operated (A working hydraulic pressure on the friction element operated then is referred to in particular as to a servo activating pressure).
In regard to a shift feel upon shifting operation, i.e., quickness and softness of shifting, the servo activating pressure has been determined in a manufacturing stage of vehicles as seen in the automatic transmission described in "MAINTENANCE MANUAL FOR RE4R01A TYPE AUTOMATIC TRANSMISSION" (A261C07) published by NISSAN MOTOR CO., LTD. in March 1987, causing an impossibility of changing the pressure in accordance with an individual taste and/or sensibility of a driver after vehicle manufacturing.
Thus, some drivers felt a great shifting shock because of too quick shifting, others an insufficiency of quickness because of too slow shifting, being obliged to ride in their vehicle without satisfaction. Additionally, in the event that the initial shift feeling was varied by reason of aged deterioration of the automatic transmission, the driver could not change it by himself so that it needed a complicated adjustment of the automatic transmission in a repair shop.
Therefore, an object of the present invention is to provide a shift control system for an automatic transmission in which the shift feel can be manually changed.
A specific object of the present invention is to provide a shift control system for an automatic transmission which induces more remarkable change of the shift feel by also changing a shift point of the automatic transmission.